During the course of World War One (1914-1918) all the nations involved needed some way to boost the moral and nationalism of both their citizens and their soldiers. Propaganda was the most popular way in which to get the desired effect. By using well thought out phrases they could provoke hate for their enemies and pride in their soldiers.
Governments could encourage young men to sign up and fight for their countries, or women to sign up as nurses. They could convince their people of the vile treatment being endured in Europe by the soldiers and boost the economy by advertising loans and products.
U.S. Propaganda Posters